The over-use of chemical fertilizers and pesticides in tandem with the Green Revolution of nineteen sixties and seventies (also known as the new seed-fertilizer-water technology) in the Indian context following two decades of their widespread application in the West, has hardened the soil, decreased its fertility, polluted air and water, and brought hazards to our health and environment. Ironically, despite the disastrous consequences of the Green Revolution in the northern parts of the country in recent years, the government seems to be in mood to spread the aftermath of this chemical-seed-fertilizer technology to other parts of the country. However, the hazards of chemical fertilizers on health and environment have been well established by studies carried out from time to time and they pose serious challenges to sustainable development. In this perspective moving towards bio-fertilizers and organic farming from a system of farming requiring high doses of chemical fertilizers and pesticides seems to be a viable alternative as the latter is observed to be friendly to health and environment.
Chemical Fertilizers and Environment
Chemical or synthetic fertilizers are basically salts by definition, and therefore, are expected to be harmful to agriculture in the long run. Yet they were promoted by their manufacturers under the misgiving that they would replenish the nutrients in the soil. Contrary to this, studies carried out from time to time have established that synthetic fertilizers tend to replenish only nitrogen, potassium, and phosphorous, while depleting other nutrients and minerals that are naturally found in fertile soil. Decrease in soil fertility also corroborated with continual use of chemical fertilizers and pesticides in the field as revealed in these studies.
Excessive use of phosphatic fertilizers cause hardening of the soil as phosphorous does not dissolve in water, while alkaline fertilizers like sodium-nitrate, basic slag develops alkalinity in soil reducing its fertility. Increasing use of chemical fertilizers also causes imbalance in quantity of specific nutrients in the soil adversely affecting, in turn, soil fertility and vegetation.
Soil fertility is also reduced due to pesticides applied to wipe out unwanted herbs in the field, insecticides meant to kill pests, and chemicals that have bio-cidal activity affecting rodents etc. Pesticides cause land degradation in various ways. They kill some useful species like the earth worms and micro-organisms that maintain the natural fertility of the soil by their activities. The bacteria or micro-organisms in the soil would normally break down organic matter into plant nutrients, and help convert nitrogen from the air into a plant-usable form. There are other useful soil bacteria such as “disease organisms” which keep cutworms, chinch bugs, grubs, and other parasites in check. Decline in the organic matter of the soil also results in hardening of the soil which, besides affecting vegetation also decreases infiltration and water retention capacity.
Besides, application of chemical fertilizers and pesticides causes contamination of the aqua system both directly and indirectly. For instance, nitrogen is toxic to fish and invertebrates. It is also toxic to humans. People who depend on rural wells for potable water have higher risk of exposure to conditions like Methemoglobinemia, and aka Blue Baby Syndrome which damages blood cells and is traced to high levels of nitrate concentration as ground water is contaminated. The herbicide atrazine, one of the most commonly used pesticides, is known to be a common water contaminant. Pesticides developed in recent years are found to be more toxic to water dwelling insects, planktons, crustaceans and fish. Even a low level of the herbicide atrazine, through contamination of streams, ponds and estuaries can be harmful to the whole aqua system. It may inhibit the growth of algae and plankton affecting the diet and reproduction of fish or other water bodies.
It has been observed that, chemical pesticides no more killed the target pests, for the latter had developed resistance absorbing the residue of such pesticides while they have hit the non-target pests, birds and micro-organisms beneficial to agriculture and environment. There are pesticides like organochlorine that are, though breakable, relatively faster than DDT, hit the non-target organisms. They enter the food chain of human-beings and remain accumulated in species like the eagle, falcon and kites. The recent decline in the eagle population is the cause of it. There are cases of decline in kite and vulture population in India due to use of pesticide of an US multinational corporation. It was banned only recently following protest by ecologists.
Again, use of pesticides not only pollutes the ecosystem contaminating the soil and acqua system, but also pollutes the air. For, even a careful spray of pesticides can make it mix in the air as vapour. As a result, there are chances of poisoning of bees and other pollinators. Thus, apart from posing a threat to biodiversity affecting flora and fauna, chemical fertilizers and pesticides destroy the environment through air, water and soil pollution.
Chemical Fertilizers, Bio-fertilizers and Our Health
Pesticides and overuse of chemical fertilizers also affect our health by retaining the residue by food chain. There are evidences of residues of pesticide in vegetables causing chronic health conditions in human-beings such as cancer and other systematic dysfunctions. Residues in food and water extend the hazards to a much wider population than that affecting the farmers alone.
A twelve-year study by researchers comparing organically grown and chemically grown foods found that synthetic nitrogen fertilizer leaves toxic nitrates in vegetables at least 16 times higher than that found in vegetables grown organically. Nitrates and residues of pesticides have oncogenic or cancer producing elements. The element omega-3 found in vegetables protects us from heart disease, cancer and Alzeimer’s disease. But it is decreasing day by day in foods chemically grown. As is obvious, these diseases were not very common before the World War II when chemical fertilizers were not used.
Scientists have found that minerals containing in the food are crucial to our health. They keep us disease free. Mere vitamins and calories are not sufficient for our survival. But it has been established by studies that chemical fertilizers and pesticides destroy the essential minerals in crops and vegetables. In comparison to vegetables grown under organic system of cultivation these minerals are found much less in quantity in chemically grown vegetables. So it is argued that the foods coming from modern agricultural methods would only fill your stomach but you remain deficient in nutrition.
Again, studies carried out by researchers in the US and UK over last seventy years has come to the conclusion that organic fruits and vegetables contained 27 per cent more vitamin C than those chemically grown. Besides, they invariably contained more minerals and much less toxic nitrates.
Bio-Fertilizers and Bio-pesticides as Alternatives
Unlike the synthetic fertilizers, bio-fertilizers would have no obnoxious problems on our health and ecosystem. Bio-fertilizers include excreta of animals such as cow-dung, vermin-compost, dhanicha (green manure), organic wastes, crop residues, manure etc having biological or organic origin. Use of bio-fertilizers brings back the natural fertility of the soil without causing harm to earth-worms and micro-organisms. Besides, these fertilizers do not leave toxic residues in the food. Far from it, they would retain the natural minerals and the plant absorbs from the soil.
Bio-fertilizers like vermin-compost will increase soil fertility and prevent hardening of the soil. The vermin and living micro-organisms in the soil would also break the naturally available nitrogen from the air for plant use. Again, it will help allowing infiltration of rain water rather than causing water-logging. The use of bio-fertilizers will have little detrimental effect on ground water as there would be little nitrogen leaching into the earth contaminating the water.
Again, the use of animal and plant wastes in the field as manures will clean the environment. The organic wastes piled up everywhere can be used as compost reducing the environmental pollution. Besides, the deposits from ponds and aquatic systems can be used as bio-fertilizers and pesticides. This will clean the aquatic system while increasing productivity in the field.
As against the poisonous chemical pesticides bio-pesticides prepared from natural biological resources like plants and standardized microbes have no harmful effects. Local bio-pesticides like neem leaf and oil, karanj (derris indica) extracts and oil, cow urine can be used as insecticide and fungicide. Unlike the chemical pesticides they do not hit the non-target pests nor do they pollute the environment.
Preparations of neem include neem cakes, neem kernel, neem oil etc. Neem leaves and oil have been used by farmers in the Indian subcontinent since time immemorial as effective pesticide and preservative as well. Scientists in India, US and Europe have discovered many properties of neem as an obnoxious pest controller. Studies have shown that instead of killing pests at one go neem serves as a pest repellant and ovipositional deterrent, that is, pests do not spread eggs on plants applied with neem extracts.
Karanj oil and preparations made from it (now available with firms manufacturing them) serve as effective insecticide and miticide. All kinds of mites causing harm to plants like the red spider mites, scarlet mites, yellow mites etc are effectively controlled by preparations made from karanj.
The development of hybrid seeds of cereals, pulses and other crops though raised the productivity and supported the growing population of the country from starvation, since the sixties, it required greater use of chemical fertilizers, some of the compounds imported from developed countries. After two decades of the Green Revolution it was found that the soil was losing its fertility demanding more and more of chemical fertilizers for the high yielding varieties (HYV) of seeds to raise productivity, while pesticides were to be used in greater doses as pests developed greater resistance. Today the situation is so acute that productivity cannot be increased without surpassing the dangerous level of fertilizer use affecting health and environment, especially in regions like Haryana and Punjab where the per capita consumption of chemical fertilizers is very high. In view of the above hazardous effects of synthetic or chemical fertilizers and pesticides, the question arises, should we continue the use of HYV seed-chemical fertilizers technology? If not, what are the alternatives? In the present context, a system of organic farming using indigenous rather than HYV seeds with bio-fertilizers and local pesticides seems to be the only solution. It is time that both the Union and State Governments should arise from their slumber and promote and propagate the system of organic farming dismantelling the use of chemical fertilizers and pesticides.